Disclosures: Dr. Hodi has received grant/research support from, and is a nonpaid consultant to, Bristol-Myers Squibb, which supported Checkmate 067. Dr. Dummer reported advising/consulting roles with the company.

MUNICH – Four years on, the combination of the immune checkpoint inhibitors nivolumab and ipilimumab as well as nivolumab alone continue to show benefit as first-line therapies for patients with advanced malignant melanoma, compared with ipilimumab monotherapy, reported investigators in the CheckMate O67 trial.

Dr. Stephen F. Hodi, Jr.

Among 945 patients with previously untreated and unresectable stage III or IV malignant melanoma, median overall survival at a minimum of 48 months follow-up had not been reached for patients assigned to the combination of nivolumab (Opdivo) and ipilimumab (Yervoy), compared with 36.9 months for patients assigned to nivolumab alone, and 19.9 months for patients assigned to ipilimumab alone, reported F. Stephen Hodi Jr., MD, of Dana-Farber Cancer Institute, Boston, and his colleagues.

“There’s a durable, sustained clinical benefit that can be achieved with first-line nivo plus ipi combination or nivo alone in patients with advanced melanoma,” he said at the European Society for Medical Oncology Congress. The study results were published online in The Lancet Oncology to coincide with the presentation.

The benefit of immunotherapy also was seen in patients whose tumors had BRAF mutations, and both the combination and nivolumab alone showed improved efficacy compared with ipilimumab alone regardless of tumor expression of the programmed death ligand-1 (PD-L1), the investigators reported.

Earlier results from the trial, reported at the 2015 annual meeting of the American Society of Clinical Oncology, showed that after a minimum of 9 months follow-up, the risk of disease progression or death was reduced by 43% with nivolumab versus ipilimumab (hazard ratio, 0.57; P less than .001) and by 58% with nivolumab plus ipilimumab vs. ipilimumab (HR, 0.42; P less than .001).

At ESMO 2018, Dr. Hodi presented 4-year follow-up results from the trial, with the analysis conducted at a minimum of 4 years after randomization of the last patient to be enrolled.

Median follow-up was 46.9 months for the nivolumab-plus-ipilimumab arm, 36 months in the nivolumab arm, and 18.6 months in the ipilimumab arm.

Median overall survival in the intention-to-treat population, a coprimary endpoint with progression-free survival (PFS), was as noted before. The HR for death with the combination compared with ipilimumab was 0.54 (P less than .0001) and for nivolumab versus ipilimumab it was 0.65 (P less than .0001).

The 4-year OS rates were 53% in the combination arm, 46% in the nivolumab-alone arm, and 30% in the ipilimumab-alone arm.

Median PFS was 11.5 months with the checkpoint inhibitor combination, 6.9 months in the nivolumab-alone arm, and 2.9 months in the ipilimumab arm.

The HR for PFS with the combination compared with ipilimumab was 0.42 (P less than .0001), and for nivolumab versus ipilimumab it was 0.53 (P less than .0001).

The safety analysis, conducted in all patients who received at least one dose of study drugs, showed that 59% of patients treated with the nivolumab/ipilimumab combination had treatment-related grade 3 or 4 adverse events, compared with 22% for patients treated with nivolumab alone, and 28% of those who received ipilimumab alone.

The most common treatment-related grade 3 adverse events were diarrhea in the combination and nivolumab-alone arms, and colitis in the ipilimumab group. In all three study arms the most common grade 4 adverse event was increased lipase.

Over the 4 years of follow-up, four patients died from treatment-related causes: one patient from cardiomyopathy and one from liver necrosis in the combination group, one from neutropenia in the nivolumab group, and one from colon perforation in the ipilimumab group. All of the deaths occurred within the first 3 years of the follow-up.

The investigators did not report on serious adverse events in the current analysis.

Invited discussant Reinhard Dummer, MD, of University Hospital Zurich Skin Cancer Center in Switzerland, said that while the study shows improved response rates and duration of response and longer PFS and OS with the combination, it’s premature to state conclusively that the combination is superior, because the study was not powered to compare efficacy between the two nivolumab-containing arms.

“So unfortunately, we have results, but we are not really convinced that the combination is so much better,” he said.

He added that the 4-year overall survival results for each arm show a consistent difference in the curves between the nivolumab and ipilimumab-alone arms. He also pointed to encouraging data showing that among patients alive at 4 years, 71% in the combination group did not require subsequent therapy, compared with 50% in the nivolumab group, and 39% in the ipilimumab group.

Dr. Hodi has received grant/research support from, and is a nonpaid consultant to, Bristol-Myers Squibb, which supported Checkmate 067. Dr. Dummer reported advising/consulting roles with the company.